Waymo is expanding its presence in Michigan, the state synonymous with the US auto industry. The Google self-driving spinoff announced Tuesday that its plan to build a 200,000-square-foot manufacturing center and hire up to 400 employees over the next five years was just approved by the state’s economic development corporation. It’s a sign that Waymo is interested in gaining more control over its production process as it seeks to grow its business of deploying autonomous vehicles.